فصلنامه سلامت و محیط زیست
سال پنجم شماره 2 (پیاپی 16، تابستان 1391)

Dioxins and Furans are dangerous and highly toxic compounds entering to the environment from natural and manmade sources. Having high stability and half-life, these compounds remain for a long period in the medium and bring about severe effects on human beings and the environment. The aim of this study was to identify dioxins and furans emission sources in Iran and to estimate their contribution in emission rate. ‌ First, we identified the emission sources of dioxins and furans and then necessary data was gathered by referring to the authorized organizations and filling the prepared UNEP questionnaires. We used Excel software to analyze the data collected. According to the results obtained, total dioxins and furan emission in Iran in 2010, was 1957 g TEQ/yr; out of this amount, 705.8 g TEQ is emitted to the atmosphere and 643.2 g TEQ is residual ash. Therefore, dioxins and furans emission rate was 26.4 µg TEQ/capita in Iran. The most rates of emissions were associated with uncontrolled open burning (732.8 g TEQ/yr) and ferrous and nonferrous metal production (635.7 g TEQ/yr) such as cupper, iron, and steel.‌ Our findings showed that the emission rate of Dioxins and Furans is much higher in Iran compared with other countries and appropriate management strategies are required to control these dangerous pollutants.

Formaldehyde is a toxic substance and harmful to human beings and the environmental health. Therefore، the effluents containing formaldehyde have to be efficiently treated before discharging into the environment. This study was aimed at investigating the efficiency of Electro-Fenton (EF) Process in pre-treating industrial wastewater containing high concentrations of formaldehyde. The effect of the important operational variables including pH، current density، H2O2 dosage، and reaction time were evaluated on the degradation of 7500 mg/L formaldehyde using batch tests. The EFP batch reactor was consisted of a cylindrical glass column with 5. 20 cm in internal diameter and 34. 50 cm in height. Working volume of the reactor was 500 mL. The maximum formaldehyde removal was obtained at alkaline pH of 10، H2O2 concentration of 10 mM/min، current intensity 8. 5 mA/cm2، and the reaction time of 6 minute. Furthermore، aerating the EFP cell could enhance the formaldehyde removal. Complete removal of formaldehyde was obtained under the abovementioned operational conditions. This study demonstrated that the EFP is capable of reducing high concentration of formaldehyde (7500 mg/l) to the level suitable for biological post-treatment.

The increasing demand for drinking water has led scientists to the use of saline waters، but existing desalinating processes are very expensive. carbon aerogel is a type of organic aerogel that is suitable for desalination owing to its unique porous structure. Low potential of fouling and deposits، very low wastewater production، electrostatic regeneration of aerogels and، in turn، no need to acid consumption، and lower power consumption are some of this technology benefits. In this experimental- analytical study، the purpose was survey of saline and brackish water desalination using carbon aerogel technology and its comparison with electrolysis. The community studied was synthetic salt water samples، using of TDS and EC indicators. The minimum synthetic samples were 243. In this regard، after polymerization of Resorsinol and Formaldehyde compounds under ambient pressure conditions and then its pyrolysis، we fabricated plates of carbon aerogel. With manufacturing in the pilot-scale، the effect of different parameters، including input salt concentration، current، water flow، distance of between electrodes and pH، on NaCl sorption amount of carbon aerogel electrodes were studied. Generally، adsorption amount increased with increasing of current and NaCl concentration and decreased with increasing of distance electrodes، flow and pH. Fabricating reactor at pilot-scale، we studied the effect of different parameters، including input salt concentration، current، water flow، intra-distance of electrodes، and pH on the NaCl sorption using carbon aerogel electrodes. Generally، adsorption capacity increased with increasing of current and NaCl concentration in the inlet flow، and it decreased with increasing intra-distance of electrodes، flow، and pH. Under the most optimal conditions، our results showed that the NaCl adsorption rate on carbon aerogel electrodes was about 1. 43×10-4 M NaCl per g of carbon aerogels indicating its cost-effectiveness.

Aniline has been used in different processes of chemical industries، however due to its side effects on the environment، several methods have been considered for its removal. In this study، we evaluated the performance of photocatalytic process using ZnO nanoparticles (nZnO) and ultraviolet (UV) irradiation for removal of Aniline from a synthetic effluent. A 5L photocatalytic reactor made from Plexiglas، which the UV lamp (20w) installed in the center of that (inside a quartz jacket)، was designed and nZnO (0. 2-0. 5 g/l) was being added into synthetic effluent with Aniline concentration of 250 ppm. After retention times of 30، 60، and 90 min، samples were centrifuged and supernatant was filtered using a 0. 2 µ PTFE filter. The liquid-liquid method and Gas Chromatography instrument was used for extraction and analysis respectively. Results showed that the photocatalytic process of nZnO+UV could effectively remove Aniline from effluent. Increasing trend in the removal efficiency of Aniline using nZnO = 0. 5 g/l was slower in comparison with other nZnO concentrations and the ANOVA analysis shows no significant difference between removal efficiency of Aniline in different concentrations of nZnO. The most removal efficiency of Aniline (76. 3%) was observed in alkaline pH، retention time of 90 min and nZnO of 0. 5 g/l. It could be concluded that the photocatalytic process of nZnO+UV could be suitable technique for Aniline removal from effluents.

Environmental pollution and health risks of dyestuffs extensively are caused by many industries. Nonbiodegradability of dyes is important so that different methods are studied for removing them. The use of white rot fungi is promising technique in this regard. Therefore, objective of this work is to investigate Rimazol Brilliant Blue Royal decolorization by immobilized Ganoderma sp. in sodium alginate from aqueous solution. This is an experimental study. First, the nutritional, environmental, and operational conditions of decolorization process were optimized. Then, efficiency of immobilized fungal cells was investigated. Experimental designs were provided using fractional factorial methods and quadratic model was fitted on decolorization data by MiniTab software. Our findings showed that type and concentration of carbon source, temperature, and pH were the most important factors affecting decolorization and statistically significant. Optimal conditions to 95.3 percent color removal were: glycerol as carbon source at 19.14 g/L; temperature, 27 oC and initial pH, 6.26. Moreover, decolorization efficiency increased from 75 percent up to 95 percent by improving process and fungal immobilization. Ganoderma fungus has suitable potential to decolorization. Besides, optimization and cell immobilization can improve its capability. Application of experimental design to research methodology is important because of decreasing in experiments and saving resources. It is suggested to use these potentials in environmental pollution control.

Irrigation of agricultural crops using wastewater will increase، in some cases، their growth by 40 to 60 percent. However، this has a high risks for human health because of the presence of higher number of pathogenic organisms. The main purpose of this study was to investigate the feasibility use of Fenton and modified Fenton with copper for the disinfection of raw wastewater.

After primarily laboratory physicochemical and biological analysis، the disinfection process was performed in three different phases in each process. First، the disinfectants were injected separately، then we performed disinfection using Fe++ and cu++ ions combined with hydrogen peroxide in order to determine synergistic effect of each catalyst. Direct method was used for fecal coliforms counting.

Hydrogen peroxide maximum efficiency for inactivation of fecal coliforms was only 0. 66log inactivation. Fenton and modified Fenton with copper ions showed a remarkable effect on the bacterial inactivation so that Fenton and modified Fenton with 1 and 2 mg/l of Cu++ inactivated coliforms by 4. 73، 3. 28، and 4. 88 log respectively.

Application of HP alone for the disinfection of raw wastewater is not practicable due to low observed efficiency. However، its combination with ions such as Fe++ and Cu++ increases HP performance in disinfection and has a notable synergistic effect on HP disinfection power، where، in the presence of each catalyst، hydrogen peroxide can reduce the fecal coliforms of raw wastewater to meet the Iranian Environmental Protection Agency Standards.

leachate from municipal solid waste landfill is a strong sewage having hazardous toxic substances. It should be treated by choosing a simple، economical، and eco-friendly method. The aim of this study is reduction of COD from the Qom City landfill leachate using electrocoagulation process. The experimental study was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0. 7 liter capacity، containing nine plate aluminum electrodes connected to a DC power supply (10-60V، 1-5A). Samples were collected in the middle of cell at regular (every 10 minutes) time intervals. The concentration of COD was determined using a COD analyzer. The effects of different parameters including current density (52. 08، 69. 44 mA/cm2)، electrolyte time (10، 20،30،40،50 and 60 min)، and voltage range (10، 20، 30، 40، 50 and 60 volt) were investigated. For a voltage of 60 V and electrolysis time 60 min، the COD removal efficiency was increased from 48. 7% for 52. 08 mA/cm2 to 77. 4% for 69. 44 mA/cm2. The highest TSS removal efficiency was obtained at the largest current input when the voltage and electrolysis time were kept at 60V and 60 min respectively. The results showed that the highest COD removal efficiency (77. 4%) was obtained when the current density was 69. 44 Ma/cm2 and the voltage and electrolysis time were kept at 60V and 60 min respectively. Power consumption for this removal level was measured to be 431. 26 kWh per kg COD removal. The results obtained revealed that the electrocoagulation technology is an effective treatment process for landfill leachate.

Presence of humic acids in water resources is important because it is a precursor to disinfection by-products (DBPs) and affects many treatment processes. In this study، we investigated the performance of electrocoagulation process duad with hydrogen peroxide (creating Fenton process) in removal of humic acids (HA) from aqueous environment. The experiments were performed using a 1 L bipolar batch reactor (covered with the aluminum foil) equipped with iron electrodes and connected to electric source having electrical potential 10 V in bipolar mode. First، reactor was filled up using aqueous solution containing 20 mg/L HA. Later، several working parameters، such as initial pH (3، 5، 7، and 8)، electrical conductivity produced from adding 1، 1. 5، 2 and 3 g/l KCl and reaction time were studied to achieve the highest humic acid removal capacity. To follow the progress of the treatment، hydrogen peroxide (50 mg/l) was added to reactor and then samples of 10 ml were taken at 5، 15، 30، 45، and 60 min and then filtered (0. 45 μ) to eliminate sludge formed during electrolysis. Finally، humic acid and iron concentration was measured using TOC analyzer and atomic absorption method respectively. Results of this study showed that the most effective removal capacities of humic acid (97. 19%) could be achieved when the pH was kept 5 (KCl 3g/l and reaction time 60 min). The share of Fenton and electrocoagulation process was %7. 9 and %92. 1 respectively. In addition، our results indicated that the removal efficiency of humic acid with increase of pH and electrical conductivity parameters decreases and increases respectively. It can be concluded that the Fenton process duad with electrocoagulation process has the potential to be utilized for cost-effective removal of humic acid from aqueous environments.

Heavy metals including antimony and cobalt as two contaminant factors leach from polyethylene terephthalate packages into water under some conditions. Therefore، their detection was concerned at different storage conditions. Five time-temperature treatments were carried out for 5 water samples. Storage conditions were defined as following: at outdoor and sunlight ambient temperature، room temperature، and at 40˚C at different intervals for 8 weeks، at 65˚C for 6 weeks and 80˚C for 7 days. Detection was performed by ICP-AES method and the data analysis was processed by SPSS software. Antimony concentration increased by storage time at all temperatures and for all samples، however enhancing proportion was different in samples. At outdoor، 40˚C and room temperature، concentration increase was below the MCL by the end of storage period. But at 65˚C and 85˚C، antimony concentration exceeded MCL by study time and the difference between samples 4 and 5، for example، was significant (p≤0. 05). Cobalt concentration at the beginning and during the study was also too less and lower than the detection limit. By increasing temperature and time، leaching of antimony into water increases. Moreover، sunlight has effect but not noticeable at the temperature of present study. In this study، blue or clear packaging had no significant effect on antimony leakage (P>0. 05).

Biological effects of non-ionizing radiation on the body of living organisms have been studied by researchers in recent years. High Voltage medical equipments are one of the sources generating electromagnetic fields. The electromagnetic field intensity of the medical equipment installed at Hamadan hospitals and the potential hazards were investigated. The main purpose of this study was to determine the intensity of the electromagnetic field around high voltage power supplies in radiology ward of the Hamadan hospitals. This was a cross-sectional study and we investigated the electromagnetic fields intensity around high voltage power supplies at Hamadan hospital wards. All measurements were performed using a calibrated Tesla-meter (HI-3603). The measurements were conducted at a range of distances varying from 25 cm to 3 m around the supporting high voltage power supply. We found that the maximum intensity of the magnetic and electric fields at a distance of less than 1 m around the high voltage power supply was 29. 625±5. 738 mGauss and 25. 17±0. 92 V/m respectively، which is less than the safe amounts recommended by the ICNIRP for occupational exposure (5000 mG and 10000 V/m) and even for public exposure (1000 mG and and 5000 V/m). The minimum intensity of EM fields for a less than 3 m distance was found to be 0. 1±0. 005 mGauss، which relates to a CT-scanner system installed at Farshchian hospital. Among the whole equipments evaluated in the current survey، the most intense magnetic and electric field was found to be for imaging technician office، which was 3. 050±0. 004 mGauss and 128. 88±0. 05 V/m respectively; it is lower than the tolerances recommended by the ICNIRP. According to our results، it seems that the EM field occupational exposure for radiation workers working at Hamadan hospitals does not exceed the tolerances recommended by the ICNIRP. Therefore، we did not find any issue related to the over-irradiation of non-ionizing among the radiologists studied. It is recommended that different brands of generators to be used in order to conduct a detailed and comprehensive study to compare the intensity of the electrical and magnetic fields.

Heat stress is considered as a serious threat to the health and safety of workers in many industries، including petrochemical and steel. Assessment of the heat stress is important from the disease prevention point of view and also for the safety and performance of workers at workplace. Although there are many indices to evaluate the heat stress، it is hard to select an applicable index for a wide range of weather conditions. The purpose of the study was to develop an optimal index based on physiological parameters in a petrochemical industry. The study was conducted in a petrochemical industry located in Assaluyeh (south of Iran). Twenty one healthy young men at different levels of fitness and heat acclimation volunteered to participate in the study. Physiological parameters including heart rate، systolic and diastolic blood pressure، skin temperature and oral temperature were measured during the working day over two consecutive weeks. Simultaneously، we measured the climatic parameters required to calculate the wet bulb globe temperature (WBGT)، required sweat rate (SWreq)، and the discomfort index (DI) indices. All the measurements took place on 2 sites: Kar (working place) and Paziresh (resting room). Our results showed that the mean values of indices and physiological parameters in Kar for both acclimated and unacclimated groups were significantly higher than Paziresh (P<0. 05). There was the strongest linear correlation between WBGT and heart rate (0. 731)، systolic blood pressure (0. 695) and diastolic blood pressure (0. 375) and skin temperature (0. 451) respectively. The amounts of DI were 0. 725، 0. 446، 0. 352، and 0. 689 respectively. But the strongest linear relationship existed between SWreq and deep body temperature (0. 766). There were significant differences in the present indices and physiological parameters of Kar and Paziresh، confirming the previous studies findings. Finally، WBGT was considered optimal index and the results revealed the almost perfect linear correlation between WBGT and heart rate. We propose WBGT can be the most applicable index for evaluating heat stress in this climate.